1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * net/sched/cls_cgroup.c Control Group Classifier
4 *
5 * Authors: Thomas Graf <tgraf@suug.ch>
6 */
7
8 #include <linux/module.h>
9 #include <linux/slab.h>
10 #include <linux/skbuff.h>
11 #include <linux/rcupdate.h>
12 #include <net/rtnetlink.h>
13 #include <net/pkt_cls.h>
14 #include <net/sock.h>
15 #include <net/cls_cgroup.h>
16 #include <net/tc_wrapper.h>
17
18 struct cls_cgroup_head {
19 u32 handle;
20 struct tcf_exts exts;
21 struct tcf_ematch_tree ematches;
22 struct tcf_proto *tp;
23 struct rcu_work rwork;
24 };
25
26 TC_INDIRECT_SCOPE int cls_cgroup_classify(struct sk_buff *skb,
27 const struct tcf_proto *tp,
28 struct tcf_result *res)
29 {
30 struct cls_cgroup_head *head = rcu_dereference_bh(tp->root);
31 u32 classid = task_get_classid(skb);
32
33 if (unlikely(!head))
34 return -1;
35 if (!classid)
36 return -1;
37 if (!tcf_em_tree_match(skb, &head->ematches, NULL))
38 return -1;
39
40 res->classid = classid;
41 res->class = 0;
42
43 return tcf_exts_exec(skb, &head->exts, res);
44 }
45
46 static void *cls_cgroup_get(struct tcf_proto *tp, u32 handle)
47 {
48 return NULL;
49 }
50
51 static int cls_cgroup_init(struct tcf_proto *tp)
52 {
53 return 0;
54 }
55
56 static const struct nla_policy cgroup_policy[TCA_CGROUP_MAX + 1] = {
57 [TCA_CGROUP_EMATCHES] = { .type = NLA_NESTED },
58 };
59
60 static void __cls_cgroup_destroy(struct cls_cgroup_head *head)
61 {
62 tcf_exts_destroy(&head->exts);
63 tcf_em_tree_destroy(&head->ematches);
64 tcf_exts_put_net(&head->exts);
65 kfree(head);
66 }
67
68 static void cls_cgroup_destroy_work(struct work_struct *work)
69 {
70 struct cls_cgroup_head *head = container_of(to_rcu_work(work),
71 struct cls_cgroup_head,
72 rwork);
73 rtnl_lock();
74 __cls_cgroup_destroy(head);
75 rtnl_unlock();
76 }
77
78 static int cls_cgroup_change(struct net *net, struct sk_buff *in_skb,
79 struct tcf_proto *tp, unsigned long base,
80 u32 handle, struct nlattr **tca,
81 void **arg, u32 flags,
82 struct netlink_ext_ack *extack)
83 {
84 struct nlattr *tb[TCA_CGROUP_MAX + 1];
85 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
86 struct cls_cgroup_head *new;
87 int err;
88
89 if (!tca[TCA_OPTIONS])
90 return -EINVAL;
91
92 if (!head && !handle)
93 return -EINVAL;
94
95 if (head && handle != head->handle)
96 return -ENOENT;
97
98 new = kzalloc(sizeof(*head), GFP_KERNEL);
99 if (!new)
100 return -ENOBUFS;
101
102 err = tcf_exts_init(&new->exts, net, TCA_CGROUP_ACT, TCA_CGROUP_POLICE);
103 if (err < 0)
104 goto errout;
105 new->handle = handle;
106 new->tp = tp;
107 err = nla_parse_nested_deprecated(tb, TCA_CGROUP_MAX,
108 tca[TCA_OPTIONS], cgroup_policy,
109 NULL);
110 if (err < 0)
111 goto errout;
112
113 err = tcf_exts_validate(net, tp, tb, tca[TCA_RATE], &new->exts, flags,
114 extack);
115 if (err < 0)
116 goto errout;
117
118 err = tcf_em_tree_validate(tp, tb[TCA_CGROUP_EMATCHES], &new->ematches);
119 if (err < 0)
120 goto errout;
121
122 rcu_assign_pointer(tp->root, new);
123 if (head) {
124 tcf_exts_get_net(&head->exts);
125 tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
126 }
127 return 0;
128 errout:
129 tcf_exts_destroy(&new->exts);
130 kfree(new);
131 return err;
132 }
133
134 static void cls_cgroup_destroy(struct tcf_proto *tp, bool rtnl_held,
135 struct netlink_ext_ack *extack)
136 {
137 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
138
139 /* Head can still be NULL due to cls_cgroup_init(). */
140 if (head) {
141 if (tcf_exts_get_net(&head->exts))
142 tcf_queue_work(&head->rwork, cls_cgroup_destroy_work);
143 else
144 __cls_cgroup_destroy(head);
145 }
146 }
147
148 static int cls_cgroup_delete(struct tcf_proto *tp, void *arg, bool *last,
149 bool rtnl_held, struct netlink_ext_ack *extack)
150 {
151 return -EOPNOTSUPP;
152 }
153
154 static void cls_cgroup_walk(struct tcf_proto *tp, struct tcf_walker *arg,
155 bool rtnl_held)
156 {
157 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
158
159 if (arg->count < arg->skip)
160 goto skip;
161
162 if (!head)
163 return;
164 if (arg->fn(tp, head, arg) < 0) {
165 arg->stop = 1;
166 return;
167 }
168 skip:
169 arg->count++;
170 }
171
172 static int cls_cgroup_dump(struct net *net, struct tcf_proto *tp, void *fh,
173 struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
174 {
175 struct cls_cgroup_head *head = rtnl_dereference(tp->root);
176 struct nlattr *nest;
177
178 t->tcm_handle = head->handle;
179
180 nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
181 if (nest == NULL)
182 goto nla_put_failure;
183
184 if (tcf_exts_dump(skb, &head->exts) < 0 ||
185 tcf_em_tree_dump(skb, &head->ematches, TCA_CGROUP_EMATCHES) < 0)
186 goto nla_put_failure;
187
188 nla_nest_end(skb, nest);
189
190 if (tcf_exts_dump_stats(skb, &head->exts) < 0)
191 goto nla_put_failure;
192
193 return skb->len;
194
195 nla_put_failure:
196 nla_nest_cancel(skb, nest);
197 return -1;
198 }
199
200 static struct tcf_proto_ops cls_cgroup_ops __read_mostly = {
201 .kind = "cgroup",
202 .init = cls_cgroup_init,
203 .change = cls_cgroup_change,
204 .classify = cls_cgroup_classify,
205 .destroy = cls_cgroup_destroy,
206 .get = cls_cgroup_get,
207 .delete = cls_cgroup_delete,
208 .walk = cls_cgroup_walk,
209 .dump = cls_cgroup_dump,
210 .owner = THIS_MODULE,
211 };
212 MODULE_ALIAS_NET_CLS("cgroup");
213
214 static int __init init_cgroup_cls(void)
215 {
216 return register_tcf_proto_ops(&cls_cgroup_ops);
217 }
218
219 static void __exit exit_cgroup_cls(void)
220 {
221 unregister_tcf_proto_ops(&cls_cgroup_ops);
222 }
223
224 module_init(init_cgroup_cls);
225 module_exit(exit_cgroup_cls);
226 MODULE_DESCRIPTION("TC cgroup classifier");
227 MODULE_LICENSE("GPL");
228
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